org.springframework.core.convert.support.ObjectToObjectConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2010 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.core.convert.support;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Collections;
import java.util.Set;
import org.springframework.core.convert.ConversionFailedException;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.ConditionalGenericConverter;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;
/**
* Generic Converter that attempts to convert a source Object to a target type
* by delegating to methods on the target type.
*
* Calls the static valueOf(sourceType) method on the target type
* to perform the conversion, if such a method exists. Else calls the target type's
* Constructor that accepts a single sourceType argument, if such a Constructor exists.
* Else throws a ConversionFailedException.
*
* @author Keith Donald
* @author Juergen Hoeller
* @since 3.0
*/
final class ObjectToObjectConverter implements ConditionalGenericConverter {
public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
Class source = sourceType.getObjectType();
Class target = targetType.getObjectType();
return (!source.equals(target) && hasValueOfMethodOrConstructor(target, source));
}
public Set getConvertibleTypes() {
return Collections.singleton(new ConvertiblePair(Object.class, Object.class));
}
public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
Class sourceClass = sourceType.getObjectType();
Class targetClass = targetType.getObjectType();
Method method = getValueOfMethodOn(targetClass, sourceClass);
try {
if (method != null) {
ReflectionUtils.makeAccessible(method);
return method.invoke(null, source);
}
else {
Constructor constructor = getConstructor(targetClass, sourceClass);
if (constructor != null) {
return constructor.newInstance(source);
}
}
}
catch (InvocationTargetException ex) {
throw new ConversionFailedException(sourceType, targetType, source, ex.getTargetException());
}
catch (Throwable ex) {
throw new ConversionFailedException(sourceType, targetType, source, ex);
}
throw new IllegalStateException("No static valueOf(" + sourceClass.getName() +
") method or Constructor(" + sourceClass.getName() + ") exists on " + targetClass.getName());
}
public static boolean hasValueOfMethodOrConstructor(Class targetClass, Class sourceClass) {
return (getValueOfMethodOn(targetClass, sourceClass) != null || getConstructor(targetClass, sourceClass) != null);
}
private static Method getValueOfMethodOn(Class targetClass, Class sourceClass) {
return ClassUtils.getStaticMethod(targetClass, "valueOf", sourceClass);
}
private static Constructor getConstructor(Class targetClass, Class sourceClass) {
return ClassUtils.getConstructorIfAvailable(targetClass, sourceClass);
}
}